The invention discloses a packaging bag sealing device which specifically comprises a base, a limiting concave plate installed at the side, close to a conveying device, of a supporting frame plate, a lifting adjusting column installed at the bottom of an inner cavity of the limiting concave plate and a sealing device body installed in the middle of a temperature control device. The sealing device body comprises a heat conducting frame plate, a heat transfer column mounted at the side, away from the temperature control device, of a strip-shaped plate body, a spherical mounting plate mounted at the side, away from the strip-shaped plate body, of the heat transfer column, a heat insulation ring mounted on the spherical mounting plate and located at the outer side of the heat transfer column, and a sealing wheel mounted at the side, away from the heat transfer column, of the spherical mounting plate. The invention relates to the technical field of packaging machines. An operation track of equipment components is limited through the arrangement of the limiting concave plate, dislocation and deviation in the movement process are avoided, the equipment components are mutually protected, and meanwhile the arrangement of the lifting adjusting column facilitates control over the distance between the components.